Communication device with phase/angle transformation and methods for use therewith

ABSTRACT

A communication device includes antennas to receive a first signal from a remote device, wherein the first signal corresponds to a first operational mode. A baseband processor selects either a first operational mode for transmitting a second signal or a second operational mode for transmitting the second signal. When the second operational mode is selected the baseband processor transforms the phase-related information corresponding to the first operational mode to transformed phase-related information corresponding to the second operational mode. The antennas transmit the second signal to the remote device in accordance with the transformed phase-related information corresponding to the second operational mode.

CROSS REFERENCE TO RELATED APPLICATIONS

The present U.S. Utility patent application claims priority pursuant to35 U.S.C. §120 as a continuation of U.S. Utility application Ser. No.13/875,907, entitled “COMMUNICATION DEVICE WITH PHASE/ANGLETRANSFORMATION AND METHODS FOR USE THEREWITH”, filed May 2, 2013, whichclaims priority pursuant to 35 U.S.C. §119(e) to U.S. ProvisionalApplication No. 61/811,916, entitled “COMMUNICATION DEVICE WITH PHASETRANSFORMATION AND METHODS FOR USE THEREWITH”, filed Apr. 15, 2013, andU.S. Provisional Application No. 61/669,621, entitled “ADAPTIVE ANGLEFEEDBACK AND BEAMFORMING WITHIN SINGLE USER, MULTIPLE USER, MULTIPLEACCESS, AND/OR MIMO WIRELESS COMMUNICATIONS”, filed Jul. 9, 2012, all ofwhich are hereby incorporated herein by reference in their entirety andmade part of the present U.S. Utility patent application for allpurposes.

BACKGROUND

1. Technical Field

The invention relates generally to communication systems; and, moreparticularly, it relates to beamforming, within single user, multipleuser, multiple access, and/or MIMO wireless communications.

2. Description of Related Art

Depending on the type of wireless communication system, a wirelesscommunication device, such as a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, etc., communicates directly orindirectly with other wireless communication devices. For directcommunications (also known as point-to-point communications), theparticipating wireless communication devices tune their receivers andtransmitters to the same channel or channels (e.g., one of the pluralityof radio frequency (RF) carriers of the wireless communication system)and communicate over that channel(s). For indirect wirelesscommunications, each wireless communication device communicates directlywith an associated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe Internet, and/or via some other wide area network.

With the proliferation of high throughput application, high data rateshave become an important issue for modern communication devices. Thefidelity of communications, however, face the scrutiny of users that arebecoming accustomed to high bandwidth and better communication quality.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an embodiment of a wirelesscommunication system.

FIG. 2 is a diagram illustrating an embodiment of a wirelesscommunication device.

FIG. 3 is a diagram illustrating an embodiment of an access point (AP)and multiple wireless local area network (WLAN) devices operatingaccording to one or more various aspects and/or embodiments.

FIG. 4 illustrates an embodiment of operation of a wirelesscommunication device in accordance with equal-gain beamforming (EGBF)and co-phased space time block coding (STBC).

FIG. 5 illustrates an embodiment of co-phased STBC and/or SFBC inaccordance with 4×1 signaling.

FIG. 6 illustrates an embodiment of co-phased STBC and/or SFBC inaccordance with 6×1 signaling.

FIG. 7 illustrates an embodiment of phase/angle information inaccordance with equal-gain EGBF and co-phased STBC.

FIG. 8 illustrates an embodiment of adaptation between operational modes(e.g., between equal-gain EGBF and co-phased STBC).

FIG. 9 illustrates an embodiment of a method adaptation betweenoperational modes.

FIG. 10 illustrates an embodiment of a method adaptation betweenoperational modes.

DETAILED DESCRIPTION

FIG. 1 is a diagram illustrating an embodiment of a wirelesscommunication system. Wireless communication system 10 includes aplurality of base stations and/or access points 12-16, a plurality ofwireless communication devices 18-32 and a network hardware component34. The wireless communication devices 18-32 may be laptop hostcomputers 18 and 26, personal digital assistant hosts 20 and 30,personal computer hosts 24 and 32 and/or cellular telephone hosts 22 and28. The details of an embodiment of such wireless communication devicesare described in greater detail with reference to FIG. 2.

The base stations (BSs) or access points (APs) 12-16 are operablycoupled to the network hardware 34 via local area network connections36, 38 and 40. The network hardware 34, which may be a router, switch,bridge, modem, system controller, etc., provides a wide area networkconnection 42 for the communication system 10. Each of the base stationsor access points 12-16 has an associated antenna or antenna array tocommunicate with the wireless communication devices in its area.Typically, the wireless communication devices register with a particularbase station or access point 12-14 to receive services from thecommunication system 10. For direct connections (i.e., point-to-pointcommunications), wireless communication devices communicate directly viaan allocated channel.

Typically, base stations are used for cellular telephone systems (e.g.,advanced mobile phone services (AMPS), digital AMPS, global system formobile communications (GSM), code division multiple access (CDMA), localmulti-point distribution systems (LMDS), multi-channel-multi-pointdistribution systems (MMDS), Enhanced Data rates for GSM Evolution(EDGE), General Packet Radio Service (GPRS), high-speed downlink packetaccess (HSDPA), high-speed uplink packet access (HSUPA and/or variationsthereof) and like-type systems, while access points are used for in-homeor in-building wireless networks (e.g., IEEE 802.11, Bluetooth, ZigBee,any other type of radio frequency based network protocol and/orvariations thereof). Regardless of the particular type of communicationsystem, each wireless communication device includes a built-in radioand/or is coupled to a radio. Such wireless communication devices mayoperate in accordance with the various aspects as presented herein toenhance performance, reduce costs, reduce size, and/or enhance broadbandapplications.

FIG. 2 is a diagram illustrating an embodiment of a wirelesscommunication device. In particular, a wireless communication device isshown that includes the host device 18-32 and an associated radio 60.For cellular telephone hosts, the radio 60 is a built-in component. Forpersonal digital assistants hosts, laptop hosts, and/or personalcomputer hosts, the radio 60 may be built-in or an externally coupledcomponent. For access points or base stations, the components aretypically housed in a single structure.

As illustrated, the host device 18-32 includes a processing module 50,memory 52, radio interface 54, input interface 58 and output interface56. The processing module 50 and memory 52 execute the correspondinginstructions that are typically done by the host device. For example,for a cellular telephone host device, the processing module 50 performsthe corresponding communication functions in accordance with aparticular cellular telephone standard.

The radio interface 54 allows data to be received from and sent to theradio 60. For data received from the radio 60 (e.g., inbound data), theradio interface 54 provides the data to the processing module 50 forfurther processing and/or routing to the output interface 56. The outputinterface 56 provides connectivity to an output display device such as adisplay, monitor, speakers, etc. such that the received data may bedisplayed. The radio interface 54 also provides data from the processingmodule 50 to the radio 60. The processing module 50 may receive theoutbound data from an input device such as a keyboard, keypad,microphone, etc. via the input interface 58 or generate the data itself.For data received via the input interface 58, the processing module 50may perform a corresponding host function on the data and/or route it tothe radio 60 via the radio interface 54.

Radio 60 includes a host interface 62, a baseband processing module 64,memory 66, a plurality of radio frequency (RF) transmitters 68-72, atransmit/receive (T/R) module 74, a plurality of antennas 82-86, aplurality of RF receivers 76-80, and a local oscillation module 100. Thebaseband processing module 64, in combination with operationalinstructions stored in memory 66, execute digital receiver functions anddigital transmitter functions, respectively. In operation, the radio 60receives outbound data 88 from the host device via the host interface62. The baseband processing module 64 receives the outbound data 88 and,based on a mode selection signal 102, produces one or more outboundsymbol streams 90.

The baseband processing module 64, based on the mode selection signal102 produces the one or more outbound symbol streams 90 from the outputdata 88. For example, if the mode selection signal 102 indicates that asingle transmit antenna is being utilized for the particular mode thathas been selected, the baseband processing module 64 will produce asingle outbound symbol stream 90. Alternatively, if the mode selectsignal indicates 2, 3 or 4 antennas, the baseband processing module 64will produce 2, 3 or 4 outbound symbol streams 90 corresponding to thenumber of antennas from the output data 88.

Depending on the number of outbound streams 90 produced by the basebandmodule 64, a corresponding number of the RF transmitters 68-72 will beenabled to convert the outbound symbol streams 90 into outbound RFsignals 92. The transmit/receive module 74 receives the outbound RFsignals 92 and provides each outbound RF signal to a correspondingantenna 82-86.

When the radio 60 is in the receive mode, the transmit/receive module 74receives one or more inbound RF signals via the antennas 82-86. The T/Rmodule 74 provides the inbound RF signals 94 to one or more RF receivers76-80. The RF receiver 76-80 converts the inbound RF signals 94 into acorresponding number of inbound symbol streams 96. The number of inboundsymbol streams 96 will correspond to the particular mode in which thedata was received. The baseband processing module 64 receives theinbound symbol streams 90 and converts them into inbound data 98, whichis provided to the host device 18-32 via the host interface 62.

In operation, one or more antennas receive a first signal from a remotedevice such as an access point or base station, station or clientdevice. The first signal is used to determine phase-related informationcorresponding to a first operational mode of the device. A basebandprocessor, such as baseband processing module 64 or other processingmodule selects either a first operational mode for transmitting a secondsignal or a second operational mode for transmitting the second signal.When the second operational mode is selected the baseband processortransforms the phase-related information corresponding to the firstoperational mode to transformed phase-related information correspondingto the second operational mode. The antennas transmit the second signalto the remote device in accordance with the transformed phase-relatedinformation corresponding to the second operational mode.

In an embodiment, the first operational mode and the second operationmode are differing ones of: a space-time block coding transmissionscheme such as co-phased space time block coding (STBC) and abeamforming transmission scheme such as equal-gain beamforming (EGBF).For example, the first operational mode is a space-time block codingtransmission scheme and the second operational mode is a beamformingtransmission scheme. Alternatively, the second operational mode is aspace-time block coding transmission scheme and the first operationalmode is a beamforming transmission scheme. Further, the basebandprocessor can select either the first operational mode for transmittingthe second signal or the second operational mode for transmitting thesecond signal, based on a measure of staleness of the phase-relatedinformation corresponding to the first operational mode. While the twooperational modes are described above in conjunction with a space-timeblock coding transmission scheme and a beamforming transmission scheme,other operational modes that rely on phase-related information canlikewise be employed.

In an embodiment, when the first operational mode is selected fortransmitting the second signal, the antennas transmit the second signalto the remote device in accordance with the phase-related informationcorresponding to the first operational mode. It should also be notedthat that device can operate to reciprocally transform phase-relatedinformation between the two operational modes. In addition to theoperation discussed above, the antenna or antennas can receive a thirdsignal from the remote device, wherein the third signal includesphase-related information corresponding to the second operational mode.The baseband processor can select one of: the first operational mode fortransmitting a fourth signal and a second operational mode fortransmitting the fourth signal. When the first operational mode isselected for transmitting the fourth signal, the baseband processortransforms the phase-related information corresponding to the secondoperational mode to transformed phase-related information correspondingto the first operational mode. The antenna or antennas transmit thefourth signal to the remote device in accordance with the transformedphase-related information corresponding to the first operational mode.

Further optional functions and features of such a communication deviceare described in conjunction with FIGS. 3-8 that follow.

FIG. 3 is a diagram illustrating an embodiment of an access point (AP)and multiple wireless local area network (WLAN) devices operatingaccording to one or more various aspects and/or embodiments. Inparticular, the features described in conjunction with radio 60 can beimplemented in AP 300 and/or WLAN devices 302, 304 and 306.

The AP 300 may compatible with any number of communication protocolsand/or standards, e.g., IEEE 802.11(a), IEEE 802.11(b), IEEE 802.11(g),IEEE 802.11(n), as well as in accordance with various aspects ofinvention. According to certain aspects of the present invention, the APsupports backwards compatibility with prior versions of the IEEE 802.11xstandards as well. According to other aspects of the present invention,the AP 300 supports communications with the WLAN devices 302, 304, and306 with channel bandwidths, MIMO dimensions, and at data throughputrates unsupported by the prior IEEE 802.11x operating standards. Forexample, the access point 300 and WLAN devices 302, 304, and 306 maysupport channel bandwidths from those of prior version devices and from40 MHz to 1.28 GHz and above. The access point 300 and WLAN devices 302,304, and 306 support MIMO dimensions to 4×4 and greater. With thesecharacteristics, the access point 300 and WLAN devices 302, 304, and 306may support data throughput rates to 1 GHz and above.

The AP 300 supports simultaneous communications with more than one ofthe WLAN devices 302, 304, and 306. Simultaneous communications may beserviced via OFDM tone allocations (e.g., certain number of OFDM tonesin a given cluster), MIMO dimension multiplexing, or via othertechniques. With some simultaneous communications, the AP 300 mayallocate one or more of the multiple antennas thereof respectively tosupport communication with each WLAN device 302, 304, and 306, forexample.

Further, the AP 300 and WLAN devices 302, 304, and 306 are backwardscompatible with the IEEE 802.11 (a), (b), (g), and (n) operatingstandards. In supporting such backwards compatibility, these devicessupport signal formats and structures that are consistent with theseprior operating standards.

Generally, communications as described herein may be targeted forreception by a single receiver or for multiple individual receivers(e.g. via multi-user multiple input multiple output (MU-MIMO), and/orOFDMA transmissions, which are different than single transmissions witha multi-receiver address). For example, a single OFDMA transmission usesdifferent tones or sets of tones (e.g., clusters or channels) to senddistinct sets of information, each set of set of information transmittedto one or more receivers simultaneously in the time domain. Again, anOFDMA transmission sent to one user is equivalent to an OFDMtransmission (e.g., OFDM may be viewed as being a subset of OFDMA). Asingle MU-MIMO transmission may include spatially-diverse signals over acommon set of tones, each containing distinct information and eachtransmitted to one or more distinct receivers. Some single transmissionsmay be a combination of OFDMA and MU-MIMO. Multi-user (MU), as describedherein, may be viewed as being multiple users sharing at least onecluster (e.g., at least one channel within at least one band) at a sametime.

MIMO transceivers illustrated may include SISO, SIMO, and MISOtransceivers. The clusters employed for such communications (e.g., OFDMAcommunications) may be continuous (e.g., adjacent to one another) ordiscontinuous (e.g., separated by a guard interval of band gap).Transmissions on different OFDMA clusters may be simultaneous ornon-simultaneous. Such wireless communication devices as describedherein may be capable of supporting communications via a single clusteror any combination thereof. Legacy users and new version users (e.g.,TGac MU-MIMO, OFDMA, MU-MIMO/OFDMA, etc.) may share bandwidth at a giventime or they can be scheduled at different times for certainembodiments. Such a MU-MIMO/OFDMA transmitter (e.g., an AP or a STA) maytransmit packets to more than one receiving wireless communicationdevice (e.g., STA) on the same cluster (e.g., at least one channelwithin at least one band) in a single aggregated packet (such as beingtime multiplexed). In such an instance, channel training may be requiredfor all communication links to the respective receiving wirelesscommunication devices (e.g., STAs).

FIG. 4 illustrates an embodiment of operation of a wirelesscommunication device in accordance with equal-gain beamforming (EGBF)and co-phased space time block coding (STBC). A transmitter 402 includesa plurality of antennas that transmit a plurality of transmit signals404 to a receiver 406. The transmitter and receiver may be anycombination of AP and STA, mobile device and base station or othertransmit and receive pair.

Considering a particular implementation where the transmitter 402includes two or more respective operational modes (e.g., EGBF andco-phased STBC), operation may be adaptive in selecting between andamong these respective operational modes. Operation of the transmitter402 in accordance with EGBF is presented in conjunction with 402′. Inthe particular the transmitter employs compensation of the phasedifference (θ) between the first antenna of a multi-antennasimplementation in each of the respective other antenna of themulti-antennas implementation. While two antennas are specificallyshown, other phase differences are applied to the other antennas. Mostgenerally a phase difference of (θ_(i)) is applied to the ith antenna.

Operation of the transmitter 402 in accordance with STBC is presented inconjunction with 402″. Co-phased STBC compensates the phase difference(θ) with respect to each pair of antennas (e.g., the first and secondantennas forming a first pair shown and a third and fourth antennasforming a second pair, etc.). Most generally a phase difference of(θ_(i)) is applied to the ith pair of antennas.

A discussed in conjunction with FIG. 2, phase-related information suchas angle/phase information between at least these two respectiveoperational modes may be reused. For example, when such phase-relatedinformation is provided in accordance with one of the respectiveoperational modes, that phase-related information they be converted foruse to operate in accordance with at least one other of the respectiveoperational modes. In such situations, regardless of the particularformat associated with phase-related information that is provided to abeamformer (e.g., as corresponding to a given operational mode), thatinformation may be converted to any desired type of feedback foroperating in accordance with any other desired operational mode. If thephase-related information is provided in accordance with the EGBFoperational mode, the phase-related information may be converted for usein accordance with the co-phased STBC operational mode. Alternatively,if the phase-related information is provided in accordance with theco-phased STBC operational mode, the phase-related information may beconverted for use in accordance with the EGBF operational mode.

FIG. 5 illustrates an embodiment of co-phased STBC and/or SFBC inaccordance with 4×1 signaling. A pair of time adjacent OFDM symbols offour symbol streams are shown for transmission by a group of fourantennas 502. The transmit and receive hardware are not specificallyshown. The channel between each antenna and the receive antenna 504 isrepresented by (h₁, h₂, h₃, h₄). As has been discussed, rotation may beperformed with respect to different antennas within different respectiveAlamouti pairs may be performed. As may be seen with respect to thisdiagram, different respective rotation may be made with respect to thedifferent individual antennas within a given Alamouti pair. That is tosay, considering and Alamouti pair corresponding to two respectiveantennas, the signaling provided to each respective antenna within thatparticular Alamouti pair may in fact undergo a different respectiverotation. For example, as may be seen with respect to this diagram thatoperates in accordance with 4×1 signaling, the antennas 3 and 4 may beoperative to transmit the same Alamouti pairs with rotation (repeatedover space). The second Alamouti pair may be viewed as being rotated tobe phase aligned with the first Alamouti pair (e.g., from certainperspectives, and implementation of being formed STBC and/or SFBC).

Assuming that h_(i)(t₀)=h_(i)(t₁) for i=1, 2, 3, 4, the receiver atantenna 504 receives the following:

$\begin{bmatrix}{y( t_{0} )} \\{y^{*}( t_{1} )}\end{bmatrix} = {{{\begin{bmatrix}{h_{1} + {c_{1}h_{3}}} & {{- h_{2}} - {c_{2}h_{4}}} \\{h_{2}^{*} + {c_{2}^{*}h_{4}^{*}}} & {h_{1}^{*} + {c_{1}^{*}h_{3}^{*}}}\end{bmatrix}\begin{bmatrix}{x( t_{0} )} \\{x^{*}( t_{1} )}\end{bmatrix}} + \begin{bmatrix}n_{0} \\n_{1}\end{bmatrix}} = {{H \times \begin{bmatrix}{x( t_{0} )} \\{x^{*}( t_{1} )}\end{bmatrix}} + \begin{bmatrix}n_{0} \\n_{1}\end{bmatrix}}}$

Generally speaking, while certain of the embodiments and/or diagramsillustrated herein may be viewed as being described with respect toSTBC, the principles described herein may also be extended to SFBC(e.g., such as being applied to adjacent sub-carriers of an OFDM system)and/or a combination of STBC and SFBC (e.g., such as in accordance withhybrid ST/FBC described above or some other implemented combination ofSTBC and SFBC).

For example, considering transmission of long training field (LTF)within a packet, two respective LTF's may be sent (e.g., a first LTFthrough antennas 1 and 3 and a second LTF through antennas 2 and 4). Thecommunication channels are then measured as h₁+c₁h₃ and h₂+c₂h₄ based onfeedback from the receiver (e.g., which would be transparent withrespect to a receiver communication device). For example, suchprocessing may be performed completely in accordance with basebandprocessing, such that no hardware modification need necessarily berequired within such operative and implemented communication devices.For example, such a transmitter communication device may actually use 4respective transmit antennas (e.g., in accordance with 4 Tx), but thepacket will appear to be 2 Tx Alamouti from the perspective of thereceiver communication device. The receiver may be implemented tooperate using Alamouti pair decoding (e.g., such as in accordance withIEEE 802.11n and/or 802.11 ac), such that no hardware modifications arerequired.

Generally speaking, as may be understood with respect to this diagramand or others employing co-phased STBC and/or SFBC, different respectiverotational values may be separately employed with respect to each of therespective antennas associated with an Alamouti pair. That is to say,rather than using a singular phase rotation or value in accordance withone or more Alamouti pairs associated with a given mode of transmission,more than one phase rotation or value may be respectively employed forthe different respective signals transmitted via different respectiveantennas within one or more Alamouti pairs.

Considering the example above for co-phase 4×1 STBC and/or SFBC,appropriately selected values for rotation may be made to maximize thediagonal terms associated with equation 1 below.

$\begin{matrix}{{H_{sq} = {{H^{*}H} = \begin{bmatrix}\Sigma & 0 \\0 & \Sigma\end{bmatrix}}}\begin{matrix}{\Sigma = {{{h_{1} + {c_{1}h_{3}}}}^{2} + {{h_{2} + {c_{2}h_{4}}}}^{2}}} \\{= {{\sum\limits_{i}\; {h_{i}}^{2}} + \lbrack {( {{c_{1}h_{1}^{*}h_{3}} + {c_{1}^{*}h_{1}h_{3}^{*}}} ) + ( {{c_{2}h_{2}^{*}h_{4}} + {c_{2}^{*}h_{2}h_{4}^{*}}} )} \rbrack}} \\{= {{\sum\limits_{i}\; {h_{i}}^{2}} + {2( {c_{2}\beta} )}}}\end{matrix}} & (1)\end{matrix}$

where α=h₁*h₃, β=h₂*h₄, and

denotes “real part”

To maximize the diagonal terms, choose

c₁=exp(jθ₁), c₂=exp(jθ₂)

with the angles

θ₁=angle(α), θ₂=angle(β)

Again, as may be understood with respect to certain embodiments and/ordiagrams herein, more than one phase rotation or value may berespectively employed for the different respective signals transmittedvia different respective antennas within one or more Alamouti pairs. Assuch, different respective of values may be used for respectivelyrotating different signal portions associated with different antennas ofone or more Alamouti pairs.

With respect to feedback provided from a receiver communication deviceto a transmitter communication device, the relatively simplest feedbackmay be composed of 2 bits (e.g., each respective c_(i) having feedbackassociated with 1 of the respective bits). For example, if the realportion associated with one of the respective values, α or β, is greaterthan zero, then the feedback bit associated with that value may be setto 1; otherwise, the feedback bit associated with that value may be setto −1.

Generally speaking, the different respective values, α or β, may beseparated out to allow for more effective fine-tuning of the realportion of signaling transmitted via the respective antennas. That is tosay, as a function of the inner product of the H matrix, individual andrespective rotation of the elements may be performed therein. As such,increased gain may be achieved by individually and selectively rotatingthe different respective signal portions transmitted via differentrespective antennas, such as within one or more Alamouti pairs.

FIG. 6 illustrates an embodiment of co-phased STBC and/or SFBC inaccordance with 6×1 signaling. As may be seen with respect to thisdiagram which includes more transmit antennas within a transmittercommunication device than that included within the prior 4×1 embodiment,there are two additional Alamouti pairs that are transmitted. A pair oftwo time adjacent OFDM symbols of six symbol streams are shown fortransmission by a group of six antennas 602. The transmit and receivehardware are not specifically shown. The channel between each antennaand the receive antenna 604 is represented by (h₁, h₂, h₃, h₄, h₅, h₆).As such, to effectuate differentiation between respective Alamoutipairs, a double valued subscript is employed for the phase rotationsrespectively provided via the use additional Alamouti pairs. Generallyspeaking, for a given rotation value, c_(i,j), the value of icorresponds to the additional Alamouti pair index, and the value of jcorresponds to the particular antenna (e.g., even or odd antenna) withina given Alamouti pair. For example, the value of c_(1,1) corresponds tothe first Alamouti pair index and the first antenna within thatparticular Alamouti pair, while the value of c_(1,2) corresponds also tothat first Alamouti pair index but instead corresponds to the secondantennas within a particular Alamouti pair.

Assuming that h_(i)(t₀)=h_(i)(t₁) for i=1, 2, 3, 4, 5, 6, the receiverat antenna 1804 receives the following:

$\begin{bmatrix}{y( t_{0} )} \\{y^{*}( t_{1} )}\end{bmatrix} = {{{\begin{bmatrix}{h_{1} + {c_{11}h_{3}} + {c_{21}h_{5}}} & {h_{2} + {c_{12}h_{3}} + {c_{22}h_{6}}} \\{{- h_{2}^{*}} - {c_{12}^{*}h_{4}^{*}} - {c_{22}^{*}h_{6}^{*}}} & {h_{1}^{*} + {c_{11}^{*}h_{3}^{*}} + {c_{21}^{*}h_{5}^{*}}}\end{bmatrix}\begin{bmatrix}{x( t_{0} )} \\{x^{*}( t_{1} )}\end{bmatrix}} + \begin{bmatrix}n_{0} \\n_{1}\end{bmatrix}} = {{H \times \begin{bmatrix}{x( t_{0} )} \\{x^{*}( t_{1} )}\end{bmatrix}} + \begin{bmatrix}n_{0} \\n_{1}\end{bmatrix}}}$

As may be seen with respect to this diagram that includes 6 respectivetransmit antennas and operate in accordance with 6×1 signaling, thereare three respective variables, α, β, and γ. As such, there are eightrespective choices respect to this embodiment 1800. Clearly, if morerespective transmit antennas are employed, then the number of variableswill increase correspondingly.

When operating to maximize the diagonal terms associated with equation 1after undergoing modification with the increased number of antennas,then the summation term within the equation 1 is modified to correspondto the equation 2 below.

$\begin{matrix}{\Sigma = {{\sum\limits_{i}\; {h_{i}}^{2}} + {2{\sum\limits_{j = 1}^{2}\; ( {{( {c_{1j}\alpha_{j}} )} + {( {c_{2j}\beta_{j}} )} + {( {c_{1j}^{*}c_{2\; j}\gamma_{j}} )}} )}}}} & (2)\end{matrix}$

where α_(j)=h_(j)*h_(j+2), β_(j)=h_(j)*h_(j+4), γ_(j)=h_(j+2)*h_(j+4)

FIG. 7 illustrates an embodiment of phase related information inaccordance with equal-gain EGBF and co-phased STBC. A 6×1 configurationis shown. As may be seen with respect to this diagram, the angle/phaseinformation for co-phased STBC 702 includes a phase rotation, c_(i,j),that is found to match the phase difference between the phase differencebetween (2i+j)^(th) transmit antenna and the j^(th) transmit antenna,where i=1, 2, . . . (Nt/2−1), j=1, 2 (index of antenna within Alamoutipair). For the 6×1 example,

angle c₁₁ c₁₂ c₂₁ c₂₂ phase h₁*h₃ h₂*h₄ h₁*h₅ h₂*h₆

Also, the angle/phase information for EGBF 704 includes a phase rotationd_(k) that is found to match the phase difference between (k−1)^(th)transmit antenna with the 1^(st) transmit antenna, where k=1, 2, . . .(Nt−1). Within this diagram, as well as others, it is noted that thesymbol ‘*’ denotes complex conjugate. Considering again the 6=1 example,

angle d₁ d₂ d₃ d₄ d₅ phase h₁h₂* h₁h₃* h₁h₄* h₁h₅* h₁h₆*

Phase/angle information between the two respective schemes may bereused. That is to say, regardless of which of the two respectiveoperational modes the information corresponds, the information may betransformed to the other of the two respective operational modes. Itshould be noted that, given the mathematical equivalence between phaseand angle information, either can be used or re-used by a transmitter.The terms angle, phase, and angle/phase are interchangeable in thisregard. Examples of such transformations are presented in conjunctionwith the examples that follow.

When the values of d_(k) derived from EGBF are available, then thecorresponding information for co-phased STBC may be determined therefrombased on the equations below.

c_(i1) = d_(2i)* c_(i2) = d₁d_((2i+1)*)

Considering the 6×1 example discussed above:

c₁₁ = d₂* c₁₂ = d₁d₃* c₂₁ = d₄* c₂₂ = d₁d₅*

Similarly, when information corresponding to co-phased STBC isavailable, then the corresponding information for EGBF may be determinedtherefrom based on the equations below.

d₁ use add'l information for d₁ d_(2k) = c_(k1)* d_((2k+1)) = d₁c_(k2)*

With respect to conversion from information provided in accordance withco-phased STBC (e.g., c_(i,j)) to information for use in accordance withEGBF, it is noted that information associated with d₁ (the difference inphase between the first two antennas) is needed. As such, whenperforming the conversion from co-phased STBC to EGBF, the additionalinformation associated with d₁ should be accounted for gathering thisadditional information, directly or indirectly, or otherwise assigningthis value, etc.

Considering the 6×1 example discussed above:

d₁ use add'l information for d₁ d₂ = c₁₁* d₃ = d₁c₁₂* d₄ = c₂₁* d₅ =d₁c₂₂*

While specific examples have been described, it should be noted that,more generally, phase-related feedback from a remote receiver inassociation with one mode of transmission, or phase-related informationgenerated based on a phase codebook, channel estimation, channelestimation codebook or other channel related feedback from a remotereceiver in association with one mode of transmission, can be used by atransmitter to derive phase information that is used to transmit signalsin another mode of transmission.

FIG. 8 illustrates an embodiment of adaptation between operational modes(e.g., between equal-gain EGBF and co-phased STBC). In particular atiming diagram is shown that presents the switching between EGBF andco-phased STBC at time intervals 800, 802, 804, 806 and 808. Whiledescribed in conjunction with EGBF and co-phased STBC, more generally,operation between any two or more operational modes may be made byreusing phase information associated with at least one of thoserespective operational modes and converting it for use in operation withone or more other of those respective operational modes. While certainembodiments presented herein relate to devices operating using tworespective operational modes, any one or more of the various aspects,embodiments, and/or their equivalents, may be extended to applicationsincluding more than two respective operational modes. When phase relatedinformation is employed in accordance with these different distinctoperational modes, adaptation and selectivity among the respectiveoperational modes may be made by converting that phase relatedinformation from any one of the operational modes to one or more otherof the respective operational modes.

As may be understood, when phase related information for EGBF isavailable, that phase related information may be reused for informationsuitable for co-phased STBC (and vice versa). Generally speaking,co-phased STBC may be viewed has having relatively more diversity gainthan EGBF and having relatively more consistent performance withinfading channel applications. As such, when phase-related informationassociated with and provided in accordance with EGBF becomes stale(e.g., after a particular period of time [which may be predetermined,fixed, adaptively determined, etc.] has passed), then that particularphase information provided in accordance with EGBF may be for co-phasedSTBC operation. Generally speaking, adaptation and selectivity may beapplied to and used to filter the particular type of phase-relatedinformation that has been provided. For example, if phase-relatedinformation provided accordance with one of the particular operationalmodes is deemed as having become stale, then phase-related informationprovided accordance with another of the particular operational modes maybe employed.

Generally speaking, if the feedback related information is fresh or notstale, then performance may be relatively better. For example, in onepossible embodiment, if the feedback related information is fresh arenot stale, then EGBF may be employed; alternatively, if the feedbackrelated information is in fact stale, then co-phased STBC may beemployed. Such adaptive selection between different respective types ofoperational modes may be made as a function of the freshness or rescindthis of the phase-related information (e.g., such as being categorizedas being either stale or not stale based on the comparison of the timesuch information was derived to the current time and a stalenessthreshold that indicates, for example, that the information is “too old”to use).

As may also be understood, if phase information for co-phased STBC isavailable, then a particular information may be reused for EGBF withadditional information for the phase difference between the first andthe second transmit antennas (e.g., d1).

In addition, when considering operation accordance with the codebookdesign (e.g., LTE), as long as the codebook operates using phaseinformation, that phase related information may be converted for usewithin other operational modes. For example, if phase relatedinformation is provided accordance with the codebook design, then it maybe converted for use within co-phased STBC as well.

Moreover, it is noted that adaptation between different respectiveoperational modes may be made. That is to say, at or during a first timeor period, operation may be performed in accordance with a first of theoperational modes. At or during a second time or period, operation maybe performed in accordance with a second of the operational modes.Adaptation between two or more respective operational modes may be madeat or during different respective times or periods. The criteria orcriteria on employed for driving such selectivity in adaptation betweenthe different respective operational modes may be varied (e.g., basedupon one or more local operating conditions or operating conditions, oneor more channel conditions, one or more historical bases correspondingto local and/or remote operating conditions, etc.).

FIG. 9 illustrates an embodiment of a method adaptation betweenoperational modes. In particular, a method is described for use inconjunction with a communication device including one or more of thefunctions and features described in conjunction with FIGS. 1-8. In step900, a first signal is received from a remote device, wherein the firstsignal corresponds to a first operational mode. Step 902 includesselecting one of: the first operational mode for transmitting a secondsignal and a second operational mode for transmitting the second signal.When the second operational mode is selected for transmitting the secondsignal, the method proceeds to transform phase-related informationcorresponding to the first operational mode to transformed phase-relatedinformation corresponding to the second operational mode as shown instep 904. Step 906 includes transmitting the second signal to the remotedevice in accordance with the transformed phase-related informationcorresponding to the second operational mode. When the first operationalmode is selected for transmitting the second signal, the method proceedsto transmit the second signal to the remote device in accordance withthe phase-related information corresponding to the first operationalmode as shown in step 908.

In an embodiment, step 902 is based on a measure of staleness of thephase-related information corresponding to the first operational mode.For example, the first operational mode can be a space-time block codingtransmission scheme and the second operational mode can be a beamformingtransmission scheme. In another example, the second operational mode canbe a space-time block coding transmission scheme and the firstoperational mode can be a beamforming transmission scheme.

FIG. 10 illustrates an embodiment of a method adaptation betweenoperational modes. In particular, a method is described for use inconjunction with a communication device including one or more of thefunctions and features described in conjunction with FIGS. 1-9. In step1000, a third signal is received from a remote device, wherein the thirdsignal corresponds to a second operational mode. Step 1002 includesselecting one of: the first operational mode for transmitting a fourthsignal and a second operational mode for transmitting the fourth signal.When the first operational mode is selected for transmitting the secondsignal, the method proceeds to transform phase-related informationcorresponding to the second operational mode to transformedphase-related information corresponding to the first operational mode asshown in step 1004. Step 1006 includes transmitting the fourth signal tothe remote device in accordance with the transformed phase-relatedinformation corresponding to the first operational mode. When the secondoperational mode is selected for transmitting the fourth signal, themethod proceeds to transmit the fourth signal to the remote device inaccordance with the phase-related information corresponding to thesecond operational mode as shown in step 1008.

It is also noted that the various operations and functions as describedwith respect to various methods herein may be performed within awireless communication device, such as using a baseband processingmodule and/or a processing module implemented therein, (e.g., such as inaccordance with the baseband processing module 64 and/or the processingmodule 50 as described with reference to FIG. 2) and/or other componentstherein including one of more baseband processing modules, one or moremedia access control (MAC) layers, one or more physical layers (PHYs),and/or other components, etc. For example, such a baseband processingmodule can generate such signals and frames as described herein as wellas perform various operations and analyses as described herein, or anyother operations and functions as described herein, etc. or theirrespective equivalents.

In some embodiments, such a baseband processing module and/or aprocessing module (which may be implemented in the same device orseparate devices) can perform such processing to generate signals fortransmission using at least one of any number of radios and at least oneof any number of antennas to another wireless communication device(e.g., which also may include at least one of any number of radios andat least one of any number of antennas) in accordance with variousaspects, and/or any other operations and functions as described herein,etc. or their respective equivalents. In some embodiments, suchprocessing is performed cooperatively by a processing module in a firstdevice, and a baseband processing module within a second device. Inother embodiments, such processing is performed wholly by a basebandprocessing module or a processing module.

As may also be used herein, the term(s) “operably coupled to”, “coupledto”, and/or “coupling” includes direct coupling between items and/orindirect coupling between items via an intervening item (e.g., an itemincludes, but is not limited to, a component, an element, a circuit,and/or a module) where, for indirect coupling, the intervening item doesnot modify the information of a signal but may adjust its current level,voltage level, and/or power level. As may further be used herein,inferred coupling (i.e., where one element is coupled to another elementby inference) includes direct and indirect coupling between two items inthe same manner as “coupled to”. As may even further be used herein, theterm “operable to” or “operably coupled to” indicates that an itemincludes one or more of power connections, input(s), output(s), etc., toperform, when activated, one or more its corresponding functions and mayfurther include inferred coupling to one or more other items. As maystill further be used herein, the term “associated with”, includesdirect and/or indirect coupling of separate items and/or one item beingembedded within another item.

As may also be used herein, the terms “processing module”, “module”,“processing circuit”, and/or “processing unit” (e.g., including variousmodules and/or circuitries such as may be operative, implemented, and/orfor encoding, for decoding, for baseband processing, etc.) may be asingle processing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module,module, processing circuit, and/or processing unit may have anassociated memory and/or an integrated memory element, which may be asingle memory device, a plurality of memory devices, and/or embeddedcircuitry of the processing module, module, processing circuit, and/orprocessing unit. Such a memory device may be a read-only memory (ROM),random access memory (RAM), volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module,module, processing circuit, and/or processing unit includes more thanone processing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,and/or processing unit implements one or more of its functions via astate machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory and/or memory element storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. Still further note that, the memoryelement may store, and the processing module, module, processingcircuit, and/or processing unit executes, hard coded and/or operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated in one or more of the Figures. Such a memorydevice or memory element can be included in an article of manufacture.

The present invention has been described above and in the claims withthe aid of method steps illustrating the performance of specifiedfunctions and relationships thereof. The boundaries and sequence ofthese functional building blocks and method steps have been arbitrarilydefined herein for convenience of description. Alternate boundaries andsequences can be defined so long as the specified functions andrelationships are appropriately performed. Any such alternate boundariesor sequences are thus within the scope and spirit of the claimedinvention. Further, the boundaries of these functional building blockshave been arbitrarily defined for convenience of description. Alternateboundaries could be defined as long as the certain significant functionsare appropriately performed. Similarly, flow diagram blocks may alsohave been arbitrarily defined herein to illustrate certain significantfunctionality. To the extent used, the flow diagram block boundaries andsequence could have been defined otherwise and still perform the certainsignificant functionality. Such alternate definitions of both functionalbuilding blocks and flow diagram blocks and sequences are thus withinthe scope and spirit of the claimed invention. One of average skill inthe art will also recognize that the functional building blocks, andother illustrative blocks, modules and components herein, can beimplemented as illustrated or by discrete components, applicationspecific integrated circuits, processors executing appropriate softwareand the like or any combination thereof.

The present invention may have also been described, at least in part, interms of one or more embodiments. An embodiment of the present inventionis used herein to illustrate the present invention, an aspect thereof, afeature thereof, a concept thereof, and/or an example thereof. Aphysical embodiment of an apparatus, an article of manufacture, amachine, and/or of a process that embodies the present invention mayinclude one or more of the aspects, features, concepts, examples, etc.described with reference to one or more of the embodiments discussedherein. Further, from figure to figure, the embodiments may incorporatethe same or similarly named functions, steps, modules, etc. that may usethe same or different reference numbers and, as such, the functions,steps, modules, etc. may be the same or similar functions, steps,modules, etc. or different ones.

Unless specifically stated to the contra, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of the various embodimentsof the present invention. A module includes a functional block that isimplemented via hardware to perform one or module functions such as theprocessing of one or more input signals to produce one or more outputsignals. The hardware that implements the module may itself operate inconjunction software, and/or firmware. As used herein, a module maycontain one or more sub-modules that themselves are modules.

While particular combinations of various functions and features of thepresent invention have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent invention is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

What is claimed is:
 1. A communication device, comprising: a pluralityof antennas to receive a first signal from a remote device, inaccordance with a co-phased space-time block coding mode; a processorthat selects one of: the co-phased space-time block coding mode fortransmitting a second signal and a beamforming mode for transmitting thesecond signal; wherein, when the beamforming mode is selected fortransmitting the second signal: the processor converts antennaphase-related information corresponding to the co-phased space-timeblock coding mode to converted antenna phase-related informationcorresponding to the beamforming mode, wherein the antenna phase-relatedinformation is one of: angle information between at least two of theplurality of antennas or phase information between at least two of theplurality of antennas; and the at least two of the plurality of antennastransmit the second signal to the remote device in accordance with theconverted antenna phase-related information corresponding to thebeamforming mode.
 2. The communication device of claim 1, wherein: theprocessor selects one of: the co-phased space-time block coding mode fortransmitting the second signal and the beamforming mode for transmittingthe second signal, based on a measure of staleness of the antennaphase-related information corresponding to the co-phased space-timeblock coding mode.
 3. The communication device of claim 1, wherein, whenthe co-phased space-time block coding mode is selected for transmittingthe second signal: the plurality of antennas transmit the second signalto the remote device in accordance with the antenna phase-relatedinformation corresponding to the co-phased space-time block coding mode.4. The communication device of claim 1 wherein: the plurality ofantennas receive a third signal from the remote device, wherein thethird signal is received accordance with to the beamforming mode; theprocessor that selects one of: the co-phased space-time block codingmode for transmitting a fourth signal and a beamforming mode fortransmitting the fourth signal; wherein, when the co-phased space-timeblock coding mode is selected for transmitting the fourth signal: theprocessor converts antenna phase-related information corresponding tothe beamforming mode to converted antenna phase-related informationcorresponding to the co-phased space-time block coding mode; and the atleast one of the plurality of antennas transmit the fourth signal to theremote device in accordance with the converted antenna phase-relatedinformation corresponding to the co-phased space-time block coding mode.5. The communication device of claim 1, wherein: the communicationdevice is an access point (AP); and the remote device is a wirelessstation (STA).
 6. The communication device of claim 1, wherein: theremote device is an access point (AP); and the communication device is awireless station (STA).
 7. A communication device, comprising: aplurality of antennas to receive a first signal from a remote device, inaccordance with a beamforming mode; a baseband processor that selectsone of: the beamforming mode for transmitting a second signal and aco-phased space-time coding mode for transmitting the second signal;wherein, when the co-phased space-time coding mode is selected fortransmitting the second signal: the baseband processor converts antennaphase-related information corresponding to the beamforming mode toconverted antenna phase-related information corresponding to theco-phased space-time coding mode, wherein the antenna phase-relatedinformation is one of: angle information between at least two of theplurality of antennas or phase information between at least two of theplurality of antennas; and the at least two of the plurality of antennastransmit the second signal to the remote device in accordance with theconverted antenna phase-related information corresponding to theco-phased space-time coding mode.
 8. The communication device of claim7, wherein: the baseband processor selects one of: the beamforming modefor transmitting the second signal and the co-phased space-time codingmode for transmitting the second signal, based on a measure of stalenessof the antenna phase-related information corresponding to thebeamforming mode.
 9. The communication device of claim 7, wherein, whenthe beamforming mode is selected for transmitting the second signal: theplurality of antennas transmit the second signal to the remote device inaccordance with the antenna phase-related information corresponding tothe beamforming mode.
 10. The communication device of claim 7 wherein:the plurality of antennas receive a third signal from the remote device,wherein the third signal is received accordance with to the co-phasedspace-time coding mode; the baseband processor that selects one of: thebeamforming mode for transmitting a fourth signal and a co-phasedspace-time coding mode for transmitting the fourth signal; wherein, whenthe beamforming mode is selected for transmitting the fourth signal: thebaseband processor converts antenna phase-related informationcorresponding to the co-phased space-time coding mode to convertedantenna phase-related information corresponding to the beamforming mode;and the at least one of the plurality of antennas transmit the fourthsignal to the remote device in accordance with the converted antennaphase-related information corresponding to the beamforming mode.
 11. Thecommunication device of claim 7, wherein: the communication device is anaccess point (AP); and the remote device is a wireless station (STA).12. The communication device of claim 7, wherein: the remote device isan access point (AP); and the communication device is a wireless station(STA).
 13. A method for use in a communication device, the methodcomprising: receiving a first signal from a remote device via at leasttwo antennas, wherein the first signal is received in accordance with afirst operational mode that corresponds to a first transmission scheme;selecting one of: the first operational mode for transmitting a secondsignal and a second operational mode that corresponds to a secondtransmission scheme for transmitting the second signal, based on ameasure of staleness of antenna phase-related information correspondingto the first operational mode that includes a phase difference betweenthe at least two antennas; when the second operational mode is selectedfor transmitting the second signal: converting the antenna phase-relatedinformation corresponding to the first operational mode to convertedantenna phase-related information corresponding to the secondoperational mode; and transmitting the second signal to the remotedevice in accordance with the converted antenna phase-relatedinformation corresponding to the second operational mode.
 14. The methodof claim 13, wherein: the first operational mode is a space-time blockcoding transmission scheme and the second operational mode is abeamforming transmission scheme.
 15. The method of claim 13, wherein:the second operational mode is a space-time block coding transmissionscheme and the first operational mode is a beamforming transmissionscheme.
 16. The method of claim 13, wherein, the method furthercomprises: when the first operational mode is selected for transmittingthe second signal: transmitting the second signal to the remote devicein accordance with the antenna phase-related information correspondingto the first operational mode.
 17. The method of claim 13, furthercomprising: receiving a third signal from the remote device, wherein thethird signal corresponds to the second operational mode; selecting oneof: the first operational mode for transmitting a fourth signal and asecond operational mode for transmitting the fourth signal; wherein,when the first operational mode is selected for transmitting the fourthsignal: converting the antenna phase-related information correspondingto the second operational mode to converted antenna phase-relatedinformation corresponding to the first operational mode; andtransmitting the fourth signal to the remote device in accordance withthe converted antenna phase-related information corresponding to thefirst operational mode.
 18. The method of claim 13, wherein: thecommunication device is an access point (AP); and the remote device is awireless station (STA).
 19. The method of claim 13, wherein: the remotedevice is a base station; and the communication device is a mobilephone.
 20. The method of claim 13, wherein: the communication device isa base station; and the remote device is a mobile phone.